Today, plastic cards such as credit cards or bank cards very often have a magnetically encoded area on their rear surface containing important information about the card owner. This magnetically encoded area very often takes the form of a black strip across the length of the card. This magnetically coded information is read by banking machines to allow the user to conduct regular banking transactions.
Sophisticated security systems also use magnetically encoded identification badges.
These cards having magnetically encoded areas are often carried by people in specially sized pockets in their wallet or purse. Unfortunately, such holders provide little protection from stray statomagnetic or electromagnetic radiation that can cause corruption of data on the card thereby rendering the card useless for all applications that require the magnetic data to be read from the card. Statomagnetic corrupting fields are not uncommon and are sometimes generated by the magnetic clasps sometimes used in purses or wallets. Electromagnetic fields are generated by the motors and components of electrical appliances.
Protective enclosures for protecting and housing magnetic cards are known. For example, Morita in U.S. Pat. No. 4,593,736 discloses a case or bag for protecting and housing cards having a magnetic strip. The case or bag is provided with a strongly magnetic outer mesh and a lining material is used to separate the card from the magnetic mesh. Other relevant prior art includes U.S. Pat. No. 4,514,586 to Waggoner.